Automatic railroad-crossing gate



` Dec. 23, 1924. 1,520,428

A. NELSON AUTOMATIC RAILROAD CROSSING GATE Filed Ooi.` l1, 1925 2 Sheets-Shee'(l l Slm/WMM Dec 23, l 924.

A. NELSON AUTOMATIC .RAILRiOAD CROSSING GATE 2 sheets-sheen 2 Filed OGC. ll, 1925 Patented Een. 23, 1924..

AXEL NELSON, OF PHILADELPHIA, PENNSYLVANIA.

AUTOMATIC RAILROAD-CROSSING GATE.

Application filed October 11, 1923.

To all whom it may concern.'

Be it known that l, AXEL NELSON, a subject of the King of Sweden, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful improvements in Automatic Railroad-Crossing Gates, of which the following is a specification.

This invention relates to railroad gates and has special reference to an electrically operated and train controlled railroad gate intended for use at street and country road intersections.

rlhe principal and most important objects of the present invention are to provide a novel and improved form of operating means for railroad gates, said means being driven by an electric motor; to provide an electric circuit for the motor which will be closed by a train entering a certain portion of the railroad and kept closed as long as the train remains in the said portion or block to provide for disconnecting the operatingmeans from the motor upon the gate reaching its lower position; and to provide gravity means for restoring the gate to lifted position and the parts of the operating mechanism to initial position upon the motor ceasing to operate through the breaking of the circuit caused by the passing of the train out of the block.

With the above and other objects in view the invention will now be described in one embodiment, particularly set forth in the appended claims and illustrated in detail in the drawings, wherein- Figure l is a side elevation of a gate shown in its relation to a roadway, the latter and the housing for the operating mechanism being shown in section.

Figure 2 is a plan view of the housing or pit for the operating mechanism, a portion of the cover being broken away to show certain parts of the mechanism in the positions assumed when the gate is fully lowered.

Figure 3 is a view at right angles to Figure l and also partly in elevation and partly in section, the parts being shown in the positions assumed when the gate is fully raised.

Figure il is a plan view of the pit with the cover removed, the parts being in the positions shown in Figure 3.

Figure 5 is a diagram showing the track and circuit arrangement used with this invention.

Figures 6 and 7 are diagrammatic views Serial No. 667,904.

showing the manner in which four gates arranged in pairs may be operated under this invention.

In the present embodiment the invention has been shown in connection with the tilt- .ing or bascule type of gate but it will be readily understood that thel operating mechanism may be used without change in other types of gates. For instance, a straight lift or portcullis gate counterbalanced to remain normally raised` may be substituted for the gate now shown. lt is accordingly to be understood that the invention is not limited to the form shown wherein there is provided an inverted U-shaped standard l0 having a cross bar ll journalled therein and carrying at each end a head or plate l2 to which is connected a respective side frame member 13 of the gate. These side frame members are shown as being of the usual converging type and extend on both sides of the pivot bar l1 to form on one side the gate proper and on the other side counterbalance arms j oincd by a bar lsupporting the counterbalance weights l5, these latter being sufficiently heavy to keep the gate proper normally raised.

.ln the present instance the standard is shown as supported directly on the cover plate 16 of a pit structure or housing 1T containing the operating mechanism. This operating mechanism includes a motor i8 on the shaft of which is fixed a gear 19 which meshes with a gear 2O carried on a shaft 2l supported in suitable bearings 22 mounted on the. door of the housing or pit. `On this shaft 2l is fixed a driving gear 23 which meshes with a barrel or drum gear 24; under certain conditions in the operation. This drum gear is fixed on a shaft 25 which is slidably and rotatably mounted in bearings 26. On the shaft 2l is also tixed a screw threaded friction drum 27 while the shaft 25 is provided with a tixedly secured friction disk 28 having ribs or flanges 29 extending peripherally therearound and engaging the thread of the drum 2T. The shaft 25 also carries a winding drum 30 which is preferably formed integral with the disk 2S and has wound thereon a cable 3l which passes upwardly out of the pit .through an opening 32 in the pit cover, being then led around an idler pulley 33 upwardly and over a pulley 84C and then downwardly having its end secured to the cross bar 14. Fixed to the bearing 26 adjacent the winding drum is a subcorresponding cavity 36. On the shaft 25,

block 40. A suitable source of powensuch f between the winding .drum and the clutch member 85 is a coiled release spring 37.

In order that the operation ofthe ydevice may be controlled in a purely automatic manner by the approach-of a train, the arrangement shown in Figure 5 is used. ln that ligure there is showng la pair of track railsiinsulated as at 39 toy formva as ithel-generatorelis-connected to= one of therails ofthe block by a wire 42'-,the\f otherrrail rof theblock being connected to'l the-motor-l81 by a wire- 4:3, the motor and-f' -pied at the start of generatorJ each Vlhaving the usual ground connectlon; Y V

Inwoperation' the gate 1s normally raised and-theA parts of the operating mechanisml arein the positions shown in Figures 3 and Ll. Underithese conditions, if a train en`l tersftheiblockftO a circuitwill be'closed throughwthe motorl'fby reason offconnection -being establishedffrom one yrail toA thel other through the axles ofthe traini The direction of the yarrowin Figure l. This will cause thel shaft'v 25v-to bedriven by the' gears 23fand' 24 and, at the same time,- thel thread `on the friction drum I27-will move the shaft? 25` longitudinally iny theV direction `of the clutch member 35 by reasonof theengagement of the thread Kwith the'iribs or flanges 29. This longitudinal movement will continue until the parts'are gear 23 and! the end# convolution of the thread onthe'ldrum 27 inC engagement-with l'hej-side of the rib v29 nearest said drum;- Meanwhile the cable has been 'wound'on the winding drum and the 'counterweight-' ed 'endfof the-gate members raised vso thaty the gate 'proper is` lowered to its closedpositi'on, being-checked when lhorizontal by l the' usual strut 44; It is obvious that-the parts are to beso adjusted that the disen- `.g'agemjentfof the gears 23'andI 24s' will take place at! the time when the strutengages the ground so thatfno damage will be done the parts. the winding drum/brings it into contact with' 'thespring 37" and the'n into engagement 'with the clutch member 35, the spring being.comp1essed in the last part of this movement. At this time longitudinal movement will cease owing to the ribs 29'having reached the end of the-screwY thread on the drum 27. Consequently `all rotation of the shaft-25 will cease `while the motor may continue to operate the shaft- 21 so long as the circuit remains closed vthrough thepresence of the train inthe block.` As s-oonlas 'the train; leavesthe block Vthe cir- The longitudinal movement of cuit will be broken and .themotor. will stop.` Restorationof thefpa'rtsi :to 'their normal positions will now take place through the gravitational effect of the counterweightswhich pull on the cable and start the sanieftoi unwind from the winding drum. This action causes the friction disk-tofrotatewthewthreaded drum 27 in the direction opposite the arrow in Figure -et and consequently thethread--williengage the ribs 29- and :longitudinale movement The gear vZet'f'will again comefinto mesh* with the gear`- v23 f andy f the movementi 'will-f f Y conti-nue until 'the gate is fully-raised-and`4` allparts restored'tobthe'l posit'onshoccui vfrictir'm drumf and disltareeprovided with? an oil lbath- 45'. v

It is obvious that theshaft 2'1"1nay extended to operate `two winding drums and thus* actuatevgatesJ-on opposite-side's of the-track, 'such ran arrangement*being4 indicated in Figures 3 and 4 where the eXl-` teiuled-shaftis shown as passi-ng'throug'h a tunnel' 46 extendingfunder the* track-.ff

This arrangementf ina :somewhat more'."

fully developed 4manner is "diagrammati-J cally shown in Figures 6 and l7 whichlalso" show `-1the= manner in'y which; 'double gates maybeoperated 'by-means ofa secondI these cables being -'led^beneath roadwayA and over suitably positioned pulleys' to operate the gates "48.-

Changes-in `the arrangement and details of the invention will readily suggest;'them-vv selves' toengineersi and others` skilled "in the art so'ftha'tthe invention isnot'to be' confined tof v'the precise embodiment" herein described, but 4`'is to? include all such asf properly come within`thescope claimed.

.Hafving thus described the invention` what is claimedas new; is:

1. The combination with a normally open"A railroad gate; of a winding druinhaving .a

cable wound thereon `and "connected tothe' gate to eife'et'closing of the' gate' upon the cablebeing wound up,a'shaftcarrying said drum, a motor vdriven shaft.; normallymesli-t ing gearsfon said shaft7 iand means to effect disengagement of one of-thel gears fromthe other uponthe ygate beingumoved to closed position.-

2. The combination withV a normallyj'openrailroad gategof a winding drum having said dr'um', a motor driven`shaft;normally meshing gears on said shafts and coacting'. l means onsaidf-shafts to canse-*one 'offthie gears to move longitudinally with respect to the other gear and thereby disengage from the last mentioned gear at a point in the operation corresponding to the closed position of the gate.

3. The combination with a. normally open railroad gate; of a winding drum having a cable Wound thereon and connected to the gate to effect closing of the gate upon the cable being wound up, a shaft carrying said drum, a motor driven shaft, normally meshing gears on said shafts, means to eect disengagement of one of the gears from the other upon the gate being moved to closed position, and a brake mechanism for the winding drum operable upon completion of the closing movement of the gate.

l. The combination with a normally open railroad gate; of a Winding drum having a cable wound thereon and connected to the gate to effect closing of the gate upon the cable being wound up, a shaft carrying said drum, a motor driven shaft, normally meshing gears on said shafts, coacting means on said shafts to cause one of the gears to move longitudinally with respect to the other gear and thereby disengage from the last men-4 tioned gear at a point in the operation corresponding to the closed position of the gate and a brake mechanism for the winding drum operable upon completion of the closing movement of the gate.

The combination with a i'notor;` of a shaft driven thereby, a second shaft journalled for rotative and longitudinal movement, meshing gears each fixed on a respestive shaft, a winding drum fixed on the second shaft, a gate, a cable connected to said gate to operate the same and having one end wound on said Winding drum, and coacting means on said shafts arranged to effect longitudinal movement of the second shaft upon rotation of the motor driven shaft whereby to disengage the gear on the second shaft from the gear on the first shaft. upon completion of a predetermined number of revolutions of the first shaft.

6. The combination with a motor; of a shaft driven thereby, a second shaft journalled for rotative and longitudinal movement, meshing gears each fixed on a respective shaft, a Winding drum fixed on the second shaft, a gate, a cable connected to sani gate to operate the same and having one ond wound on said Winding drum, and coaction means on said shafts arranged to effect longitudinal movement of the second shaft upon rotation of the motor driven shaft whereby to disengage the gear on the second shaft from the gear on the first shaft upon completion of a predetermined nurnber of revolutions of the first shaft, said coacting means comprising a drum on the first shaft having a screw thread thereon, and a disk on the second shaft having a peripheral rib engaging said thread, said threaded drum and disk also constituting friction gearing whereby the second shaft may drive the first shaft upon unWinding of the cable in opening movement of the gate.

7. rlhe combination with a motor; of a shaft driven thereby, a second shaft journalled for rotative and longitudinal movement, meshing gears each fixed on a respective shaft, a winding drum fixed on the second shaft, a gate, a cable connected to said gate to operate the same and having one end wound on said winding drum, coacting means on said shafts arranged to effect longitudinal movement of the second shaft upon rotation of the motor driven shaft whereby to disengage the gear on the second shaft from the gear on the first shaft upon completion of a predetermined number of revolutions of the first shaft, and braking means engaging the winding drum to prevent driving thereof by the friction gearing upon disengagement of the first mentioned gears.

8. rl`he combination with a motor; of a shaft driven thereby, a second shaft journalled for rotative and longitudinal movement, meshing gears each fixed on a respective shaft, a winding drum fixed on the second shaft, a gate, a cable connected to said gate to operate the same and having one end wound on said Winding drum, coacting means on said shafts arranged to effect longitudinal movement of the second shaft upon rotation of the motor driven shaft whereby to disengage the gear on the second shaft from the gear on the first shaft upon completion of a predetermined number of revolutions of the first shaft, and coact ing means comprising a drum on the first shaft having a screw thread thereon, and a disk on the second shaft having a peripheral rib engaging said thread, said threaded drum and disk also constituting friction gearing whereby the second shaft may drive the first shaft upon unwinding of the cable in opening movement of the gate, braking means engaging the winding drum to prevent driving thereof by the friction gearing upon disengagement of the first mentioned gears and train controlled means for closing` a circuit through said motor.

In testimony whereof I affix my signature.

AXEL NELSON. 

